EXC_BAD_ACCESS crash when stopping MPMoviePlayerController - ios

Question

I am having some EXC_BAD_ACCESS problems whilst trying to stop a video that is being played through MPMoviePlayerController. Here is some code:
Video Class:
#interface MyVideo()
#property (nonatomic, strong) MPMoviePlayerController * videoController
#end
#implementation MyVideo
#synthesize videoController;
- (MyVideo*) initIntoView: (UIView*) view withContent (NSDictionary*) contentDict {
self=[super init];
NSString * rawUrl=[[NSString alloc] initWithFormat:#"http://.../%#.mp4", [contentDict objectForKey:#"filename"]];
NSURL * videoUrl=[[NSURL alloc] initWithString:rawUrl];
videoController = [[MPMoviePlayerController alloc] initWithContentURL:videoUrl];
videoController.movieSourceType=MPMovieSourceTypeFile;
videoController.view.frame = viewRef.bounds;
[videoController.view setAutoresizingMask:UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight];
videoController.controlStyle=MPMovieControlStyleNone;
[view addSubview:videoController.view];
return self;
}
/* other code */
- (void) stop {
NSLog(#"video stop");
[videoController stop];
}
#end
This MyVideo class is a property within my AppDelegate class, like so:
#property (nonatomic, strong) MyVideo video;
A line in my AppDelegate class fires off the public method stop of this MyVideo class, like so:
[video stop];
This usually works fine. But occasionally I get an EXC_BAD_ACCESS error on the line with [videoController stop]. The line before it, the one with NSLog on it, outputs to the console as expected.
This crash happens while the video that has been loaded into the videoController is still playing. But it does not happen every time.
Can anyone suggest why this crash is happening? I suspect its because videoController is no longer in memory, despite it being strong and still in use.
Am I right in thinking there is absolutely no way of testing the videoController to see if it is still in memory?
Am I right in thinking there is absolutely no way of forcing videoController to stay in memory while it is being used to play a video?
So instead of trying to stop the video and shut down the MyVideo class properly when I dont want to play the video anymore, I am now thinking of just setting the MyVideo class to nil, and let ARC deal with stopping the video and clearing it from memory. Is this the right way of doing this? Would there be any disadvantages to this?
Are there any other solutions to this problem that I am missing?

Answer 1

With EXC_BAD_ACCESS my first port of call is to enable Zombie Objects in my Debug Scheme.
This should give you an idea of what object is causing the EXC_BAD_ACCESS. Just to double check it is your videoController.
When does your stop function get called on MyVideo
Is the crash on specific devices, iPad iPod, does it occur on specific os's iOS 6,7
Is it the same video file?
It cant randomly break there must be some pattern that is causing the EXC_BAD_ACCESS

Answer 2

I may be wrong but I have a feeling that its a threading issue. I suspect the thread calling the [myVideo stop] function is not aware of the videoController(probably initialised on the main thread). Try calling the [videoController stop] within the main thread by using the following:
dispatch_async(dispatch_get_main_queue(), ^{
[videoController stop];
});
Do let me know if this works!